Display screens are becoming increasingly prevalent in daily life, and are commonly used to present information to groups of people, or to individuals, by using television/video screens, projectors, video advertising screens, and mobile devices such as mobile phones, tablets, laptops and so on.
There is an issue in that the information on these display screens is available to anyone in visual range. Information and content viewed on a display device cannot be guaranteed to be transmitted in a manner that allows only the intended audience to view it. Anyone able to see a screen can see the content, and when sensitive or confidential information is displayed on these screens, there is no way to control who can see this information without physically obscuring the line of sight to the display. This causes a potential security risk, whereby anyone can see content on a given screen, and also places a limitation on the information that an audience can see at any one time with a single video sequence on a display.
It is an aim of embodiments described herein to provide a way of allowing content on a display screen to be securely delivered to selected users.